US7096972B2 - Hammer drill attachment - Google Patents

Abstract

Power tools of the type under consideration include hammer drills, for example, which are electric or battery powered and includes two modes of operation: a rotation mode and a rotation-hammer mode. A manually operable selector lever enables the hammer drill to be selectively operated in one of the two modes by disengaging and engaging a hammer mechanism. In rotation-hammer mode, the drive shaft of the hammer drill rotates a tool element about a rotational axis and oscillates the tool element along a rotational axis. An attachment mountable within the chuck of a hammer drill prevents a tool element from rotating when the hammer drill is operating in rotation-hammer mode. The hammer drill attachment transfers hammer action, but not rotation, to the tool element. The hammer drill attachment enables dual function power tools to be operated in a hammer only mode to perform a function, for example, chiseling.

Description

FIELD OF THE INVENTIONS

The present invention relates generally to power tools. More specifically, the present invention relates to attachments for power tools having hammer mechanisms and selectively operable in either a rotation mode or rotation-hammer mode.

BACKGROUND OF THE INVENTIONS

Power tools of the type under consideration include hammer drills, for example, which are electric or battery powered and includes two modes of operation: a rotation mode and a rotation-hammer mode. A manually operable selector lever enables the hammer drill to be selectively operated in one of the two modes by disengaging a hammer mechanism when the selector lever is placed in a first position and engaging the hammer mechanism when the selector lever is placed in a second position.

When the selector lever is placed in the first position, the power tool operates in a rotation action mode. This mode is selected for rotating a tool element, such as a drill bit, in order to drill a hole in material such as wood or plaster.

When the selector lever is placed in the second position, the power tool operates in a rotation-hammer action mode in which a hammer action works in combination with rotation to rotate and hammer a tool element. One well-known use of the simultaneous rotation and hammer action of the rotation-hammer mode is to drill a hole in resistant material such as steel or concrete. When the power tool operates in the rotation-hammer mode, the operator must exert a pressing force or contact pressure to the tool element positioned in the chuck in order to actuate the hammer mechanism.

The manually operable selector lever determines operation of such hammer drills having the dual function of rotation mode and rotation-hammer mode. Operators of these dual function power tools often find it necessary to perform work that requires the tool to be operated solely in a hammer action mode, such as chiseling. However, a sole hammer action mode is not available in such dual function power tools. Although power tools, such as rotary hammers, exist with three modes of operation: a rotation mode, a rotation-hammer mode, and a hammer or chiseling mode, these power tools are more expensive than the dual mode power tools discussed above. An object of the present invention is to enable dual function power tools, such as hammer drills having a rotation mode and a rotation-hammer mode, to be operated in a hammer only mode.

The various aspects, features and advantages of the present invention will become more fully apparent to those having ordinary skill in the art upon careful consideration of the following Detailed Description of the Inventions with the accompanying drawings described below.

SUMMARY OF THE INVENTIONS

An object of the present invention is to provide an additional mode of operation, a hammer only action mode, to power tools such as hammer drills that only have two modes of operation: a rotation mode and a rotation-hammer mode. The present invention may be summarized as an attachment mountable within the chuck of a hammer drill. The hammer drill attachment comprises a body having a longitudinally extending inner portion with a first end and a second end and a drill member positioned within the second end of body, wherein drill member longitudinally oscillates along a rotational axis between a first position and a second position within body. In rotation-hammer mode, the drive shaft of the hammer drill rotates the drill member about a rotational axis and oscillates the drill member along a rotational axis.

According to the present invention, the hammer drill attachment prevents a tool element positioned in the first end of the body from rotating when the hammer drill is operating in rotation-hammer mode. The operator exerts a pressing force or contact pressure to engage the hammer mechanism of the hammer drill. The hammer drill attachment transfers hammer action, but not rotation, to the tool element. An object of the present invention is to enable dual function power tools, such as hammer drills having a rotation mode and a rotation-hammer mode, to be operated in a hammer only mode. Preferable embodiments for mere illustration will be described as follows.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a hammer drill according to the present invention.

FIG. 2 is an exploded schematic diagram of a hammer drill attachment for use with the hammer drill ofFIG. 1 in accordance to a preferred embodiment of the present invention.

FIG. 3 is a perspective view of an assembled hammer drill attachment according to a preferred embodiment the present invention.

FIG. 4 is a perspective view of an assembled hammer drill attachment in accordance with an alternate preferred embodiment of the present invention.

FIG. 5 is a cross sectional view of a hammer mechanism in rotation action mode.

FIG. 6 is a cross sectional view of a hammer mechanism in a first position in rotation-hammer action mode.

FIG. 7 is a cross sectional view of a hammer mechanism in a second position in rotation-hammer action mode.

FIG. 8 is a cross sectional view of a hammer drill attachment in a first position in accordance with a preferred embodiment of the present invention.

FIG. 9 is a cross sectional view of a hammer drill attachment in a second position in accordance with a preferred embodiment of the present invention.

FIG. 10 is a cross sectional view of a hammer drill attachment in a first position in accordance with an alternate preferred embodiment of the present invention.

FIG. 11 is a cross sectional view of a hammer drill attachment in a second position in accordance with an alternate preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTIONS

FIG. 1 is a schematic diagram of a hammer drill according to the present invention. As illustrated inFIG. 1, ahammer drill100 includes ahandle102 as well as an optionalauxiliary handle104 to enable an operator to grasphammer drill100 during operation. Ahousing101 includes the inner workings ofhammer drill100 including a motor and a hammer mechanism300 (FIG. 5). A manually operable selector lever106 engages and disengages the hammer mechanism so that whenselector lever106 is placed in a first position relative to aside portion105 ofhammer drill100,hammer drill100 operates in a rotation action mode, and whenselector lever106 is placed in a second position relative toside portion105,hammer drill100 operates in a rotation-hammer action mode. Atrigger108 is used to actuate an electric, battery powered, or pneumatic motor (not shown) ofhammer drill100.

Engagement oftrigger108 by an operator drives the motor at variable speeds, dependant upon the amount of force exerted by the operator to press trigger inward towardshandle102, thereby actuating the electric, battery powered, or pneumatic motor to drive the drive shaft302 (FIG. 5). When manuallyoperable selector lever106 is in the first position,drive shaft302 is rotatable about arotational axis110 in a direction indicated by arrow A. When manuallyoperable selector lever106 is in the second position,drive shaft302 is rotatable aboutrotational axis110 in direction indicated by arrow A and longitudinally oscillates alongrotational axis110 in a direction indicated by arrow B. In order fordrive shaft302 to longitudinally oscillate alongrotational axis110 in the direction of arrow B, the operator must exert a pressing force or contact pressure to a tool element positioned in adrill chuck112.

Drill chuck112 mounts ondrive shaft302 ofhammer drill100 and includes areceptacle114 having a plurality of jaws that secure the shank of the tool element, described in detail below, when the tool element is positioned withinchuck112. There are several methods for securing the tool element intochuck112, such as through the use of a keyed chuck, a keyless chuck, or a quick-connection mechanism. A keyed chuck has a plurality of ridges around the base circumference ofchuck112. A key, which is inserted within a side ofchuck112, has ridges that mate with the ridges around the base circumference ofchuck112. The ridges of the key move within the ridges around a base circumference ofchuck112 so that when the key is rotated counter-clockwise, a plurality of jaws within achuck receptacle114 open as to enable the shank of the tool element to be inserted withinchuck112 atchuck receptacle114. Once the tool element is positioned withinchuck112, the key is rotated clockwise to secure the shank of the tool element by fixedly engaging the plurality of jaws withinchuck receptacle114 around shank of tool element.

With a keyless chuck,chuck112 rotates counter-clockwise to open the plurality of jaws withinreceptacle114 to enable the tool element to be inserted withinchuck112 atchuck receptacle114. Chuck112 is rotated counter-clockwise either manually or by pressingtrigger108 in a reverse mode. Once the tool element is positioned withinchuck112,chuck112 is rotated clockwise to secure the shank of tool element by fixedly engaging the plurality of jaws withinchuck receptacle114 around shank of tool element. Chuck112 is rotated clockwise either manually or by pressingtrigger108 in the drive mode.

With a quick-connection chuck,chuck112 is pressed backward to open the plurality of jaws withinchuck receptacle114. The plurality of jaws are keyed with SDS grooves or a hexagonal configuration. Once the tool element is inserted,chuck112 is released to the original position securing the shank of tool element. Tool element shanks have SDS grooves used in conjunction with a SDS quick-connection chuck or a hexagonal contour used in conjunction with a hexagonal configured chuck.

Hammer drills have, but are not limited to, a ⅜″, ½″, ¾″, or 1″ chuck which designates the maximum size of the tool element shank that can be inserted intochuck receptacle114. Therefore, the tool elements to be used in conjunction with these hammer drills must have either a ⅜″, ½″, ¾″, or 1″ respectively or lesser size shank in order to engage intochuck112. Most power tools designate the maximum size diameter of the shaft of the tool element that can be inserted intochuck receptacle114.

FIG. 2 is an exploded schematic diagram of a hammer drill attachment for use with the hammer drill ofFIG. 1 in accordance to a preferred embodiment of the present invention. As illustrated inFIG. 2, ahammer drill attachment200 that allows a hammer drill operating in the rotation-hammer mode to exert a hammer only action to a tool element includes alongitudinal body202 and adrill member212.Longitudinal body202 extends from afirst end204 to asecond end206. According to the present invention,body202 is cylindrical, but is not limited thereto.Body202 has afirst opening208 and asecond opening210 forming a longitudinally extendinginner portion207 extending fromfirst end204 tosecond end206 for inserting adrill member212 withinbody202.

Shaft216 ofdrill member212 extends outward from abase end214 ofdrill member212.Base end214 has a diameter that enablesbase end214 to be inserted infirst opening208 ofbody202 throughinner portion207 so thatshaft216 extends outsidebody202 throughsecond opening210 atsecond end206 andbase end214 is positioned ininner portion207 atsecond end206.Shaft216 can be of any size diameter, for example ⅜″ or ½″, to fit within a keyed chuck, keyless chuck, or quick-connection receptacle. In an alternate preferred embodiment,shaft216 has a SDS configuration or hexagonal contour to engage into a SDS quick-connection chuck or hexagonal contour quick-connection chuck, respectively. The quick-connection allows for rapid loading and unloading ofdrill member212 intoreceptacle114 ofchuck112.

Tool element218 is selected to perform the function the operator desires, and includes a workingend220 and ashank222.Shank222 has a diameter that enablesshank222 to be inserted withinfirst opening208 ofbody202. Workingend220 oftool element218 makes contact with the working surface. Workingend220 can be of varying shapes and sizes in order to perform the function the operator desires, for example a chisel.

FIG. 3 is a perspective view of an assembled hammer drill attachment according to a preferred embodiment the present invention. As illustrated inFIG. 3drill member212 is inserted withinfirst opening208 and throughinner portion207 ofbody202.Drill member212 is positioned so thatbase end214 is positioned withininner portion207 atsecond end206 ofbody202 andshaft216 is extended outsidebody202 throughsecond opening210 atsecond end206. Rim213 (FIG. 8) retainsbase end214 ofdrill member212 withininner portion207 ofbody202 and preventsbase end214 from extending outsidesecond opening210 ofsecond end206.Drill member212 is free to rotate about rotational axis110 (FIG. 1) ofhammer drill100 and longitudinally oscillate alongrotational axis110 betweenfirst end204 andsecond end206 ofinner portion207 ofbody202.Shaft216 extends outsidesecond end206 ofbody202 so thatshaft216 is insertable withinreceptacle114 of chuck112 (FIG. 1).

Shank222 oftool element218 is inserted withinfirst opening208 offirst end204 ofbody202.Tool element218 is secured withininner portion207 ofbody202 by any means known to those skilled in the art. In a preferred embodiment,shank222 oftool element218 is secured withinfirst opening208 ofbody202 with Allen screws by rotating anAllen screw211 to extendAllen screw211 withinbody202 to fixedly engageshank222 withininner portion207 ofbody202. In a second embodiment,shank222 oftool element218 has a quick-connection configuration, such as a SDS, to mate with a quick-connection configuration offirst end204 ofbody202. The quick-connection allows for rapid loading and unloading of tool elements withinbody202.

FIG. 4 is a perspective view of an assembled hammer drill attachment in accordance with an alternate preferred embodiment of the present invention. As illustrated inFIG. 4, according to an alternate preferred embodiment of the present invention,drill member212 is integrated withbody202.Body202 includes asection400 perpendicular to theinner portion207.Drill member212 is inserted withinfirst opening208 and throughinner portion207 ofbody202.Drill member212 is positioned so thatbase end214 is positioned withininner portion207 atsecond end206 ofbody202 andshaft216 is extended outsidebody202 throughsecond opening210 atsecond end206.Section400 is welded withininner portion207 ofbody207 to preventdrill member212 from extending outward fromfirst opening208 offirst end204 ofbody202.Section400 retainsdrill member212 withininner portion207 ofbody202 and preventsbase end214 from departing outsidefirst opening208 offirst end204. Therefore,body202 anddrill member212 are integrated as one piece. Rim213 (FIG. 8) retainsbase end214 ofdrill member212 withininner portion207 ofbody202 and preventsbase end214 from extending outsidesecond opening210 ofsecond end206.Drill member212 is free to rotate about rotational axis110 (FIG. 1) ofhammer drill100 and longitudinally oscillate alongrotational axis110 betweenfirst end204 andsection400 ofinner portion207 ofbody202.Shaft216 extends outsidesecond end206 ofbody202 so thatshaft216 is insertable withinreceptacle114 of chuck112 (FIG. 1).

Shank222 oftool element218 is inserted withinfirst opening208 offirst end204 ofbody202 so thatshank222 is positioned againstsection400 ofbody202.Tool element218 is secured withininner portion207 ofbody202 by any means known to those skilled in the art. In a preferred embodiment,shank222 oftool element218 is secured withinfirst opening208 ofbody202 with Allen screws by rotating anAllen screw211 to extendAllen screw211 withinbody202 to fixedly engageshank222 withininner portion207 ofbody202. In a second embodiment,shank222 oftool element218 has a quick-connection configuration, such as a SDS, to mate with a quick-connection configuration offirst end204 ofbody202. The quick-connection allows for rapid loading and unloading of tool elements withinbody202.

According to a preferred embodiment of the present invention,body202,drill member212, andtool element218 are manufactured from, but not limited to, steel or carbide. From the description above, two embodiments of the present invention are possible, but not limited thereto: first,body202, anddrill member212 are separate parts; second,body202 anddrill member212 are integrated as one part.

FIG. 5 is a cross sectional view of a hammer mechanism in rotation action mode.Hammer mechanism300 is located inhousing101 ofhammer drill100. As illustrated inFIG. 5,hammer mechanism300 includes adrive shaft302 and two opposing clutches: afixed clutch304 and arotating clutch306. A series of ramps are located on fixedclutch304 androtating clutch306.Fixed clutch304 has a first set oframps308 androtating clutch306 has a second set oframps310. Rotating clutch306 and fixed clutch304 are not positioned together during rotation only mode. When manually operable selector lever106 (FIG. 1) is in the first position relative to a side portion105 (FIG. 1),drive shaft302 is rotatable aboutrotational axis110. Engagement of trigger108 (FIG. 1) by an operator drives the motor at variable speeds, dependant upon the amount of force exerted by the operator to press trigger inward towards handle102 (FIG. 1), thereby actuating the electric, battery powered, or pneumatic motor to drive thedrive shaft302. Driveshaft302 rotates chuck112 (FIG. 1) andtool element218 positioned inchuck112 aboutrotational axis110.

Hammer mechanism is engaged when manually operable selector lever106 (FIG. 1) is in the second position relative to a side portion105 (FIG. 1) ofhammer drill100.Hammer mechanism300 is actuated when an operator applies a pressing force or contact pressure totool element218 positioned in chuck112 (FIG. 1) while engaging trigger108 (FIG. 1). When an operator applies a pressing force or contact pressure totool element218 positioned in chuck112 (FIG. 1),rotating clutch306 and fixed clutch304 are positioned together so that second set oframps310 onrotating clutch306 slide up and down first set oframps308 on fixed clutch304 causingdrive shaft302 to longitudinally oscillate alongrotational axis110 from a first position to a second position, creating a hammer action.

FIG. 6 is a cross sectional view of a hammer mechanism in a first position in rotation-hammer action mode. As illustrated inFIG. 6,rotating clutch306 and fixed clutch304 are positioned together when the hammer mechanism is actuated. In the first position, driveshaft302 rotates aboutrotational axis110 and driveshaft302 longitudinally regresses alongrotational axis110 when second set oframps310 onrotating clutch306 slide down first set oframps308 on fixedclutch304.

FIG. 7 is a cross sectional view of a hammer mechanism in a second position in rotation-hammer action mode. As illustrated inFIG. 7,rotating clutch306 and fixed clutch304 are positioned together when the hammer mechanism is actuated. In the second position, driveshaft302 rotates aboutrotational axis110 and driveshaft302 longitudinally advances alongrotational axis110 when second set oframps310 onrotating clutch306 slide up first set oframps308 on fixedclutch304.

Hammer drill attachment200 (FIG. 2) is secured by one of the methods described above tohammer drill100 by insertingshaft216 ofdrill member212 within chuck receptacle114 (FIG. 1).Shaft216 has a diameter that enablesshaft216 to be fixedly engaged withinchuck receptacle114.Shaft216 can be of any size diameter, for example ⅜″ or ½″, to fit within a keyed chuck, keyless chuck, or quick-connection chuck. In a preferred embodiment, asdrill member212 rotates aboutrotational axis110 and longitudinally oscillates alongrotational axis110 withinbody202,hammer drill attachment200 transfers hammer action but not rotation action totool element218.

FIG. 8 is a cross sectional view of a hammer drill attachment in a first position in accordance with a preferred embodiment of the present invention.FIG. 9 is a cross sectional view of a hammer drill attachment in a second position in accordance with a preferred embodiment of the present invention. As the hammer mechanism is actuated so that second set oframps310 onrotating clutch306 slide up and down first set oframps308 on fixed clutch304 (FIG. 6 andFIG. 7),drill member212 longitudinally advances and regresses alongrotational axis110 throughinner portion207 ofbody202 between a first position, in which base214 ofdrill member212 is positioned againstsecond end206 ofbody202, and a second position, in which base214 ofdrill member212 is positioned againstshank222 oftool element218. Whendrill member212 is in the first position,rim213 retainsbase end214 ofdrill member212 withinbody202 and preventsbase end214 from extending outsidesecond opening210 ofsecond end206.

Asdrill member212 rotates aboutrotational axis110 and longitudinally oscillates alongrotational axis110 withinbody202, hammer action is transferred totool element218 whendrill member212 longitudinally oscillates between a first position and a second position. Rotation is not transferred totool element218 sincedrill member212 andtool element218 are independent parts withinbody202. Therefore, a function that requires hammer only action, such as chiseling, can be performed.

FIG. 10 is a cross sectional view of a hammer drill attachment in a first position in accordance with an alternate preferred embodiment of the present invention.FIG. 11 is a cross sectional view of a hammer drill attachment in a second position in accordance with an alternate preferred embodiment of the present invention. As the hammer mechanism is actuated so that second set oframps310 onrotating clutch306 slide up and down first set oframps308 on fixed clutch304 (FIG. 6 andFIG. 7),drill member212 longitudinally advances and regresses alongrotational axis110 throughinner portion207 ofbody202 between a first position, in which base214 ofdrill member212 is positioned againstsecond end206 ofbody202, and a second position, in which base214 ofdrill member212 is positioned againstsection400 ofinner portion207. Whendrill member212 is in the first position,rim213 retainsbase end214 ofdrill member212 withinbody202 and preventsbase end214 from extending outsidesecond opening210 ofsecond end206.

Asdrill member212 rotates aboutrotational axis110 and longitudinally oscillates alongrotational axis110 withinbody202, hammer action is transferred totool element218 whendrill member212 moves between a first position and a second position.Drill member212 transfers hammer action toperpendicular section400 that in turn delivers hammer action totool element218. Rotation is not transferred totool element218 sincedrill member212 andtool element218 are independent parts withinbody202. Therefore, a function that requires hammer only action, such as chiseling, can be performed.

Body202 prevents the rotational component of the rotation-hammer action mode from transferring totool element218. According to the present invention,body202 anddrill member212 provide a hammer only mode to dual mode hammer drills.

While the present inventions and what is considered presently to be the best modes thereof have been described in a manner that establishes possession thereof by the inventors and that enables those of ordinary skill in the art to make and use the inventions, it will be understood and appreciated that there are many equivalents to the exemplary embodiments disclosed herein and that myriad modifications and variations may be made thereto without departing from the scope and spirit of the inventions, which are to be limited not by the exemplary embodiments but by the appended claims.

Claims (5)

1. A hammer drill attachment comprising:

a hammer drill, a tool element, and a chuck;

a cylindrical body having a first opening extending to a second opening forming an inner portion;

a rim positioned at said second opening of said body and extending substantially within said inner portion;

said tool element having a shank and a working end, wherein said shank is positioned within said first opening of said body and extending substantially within said inner portion;

a cylindrical drill member with a base end and a shaft, wherein said base end has a substantially larger cylindrical diameter than said shaft;

said base end is positioned within said second opening of said body and extending substantially within said inner portion, said shaft is positioned within said chuck of said hammer drill;

said drill member longitudinally oscillates along a rotational axis through said inner portion from a first position and a second position, wherein said base end of said drill member momentarily and directly abuts said shank of said tool element at said second position and said base end of said drill member momentarily abuts said rim at said first position, wherein said rim retains said base end within said inner portion for preventing rotation of said tool element with respect to said body when said hammer drill is operating in a rotation-hammer mode.

2. The system for preventing rotation to a tool element in the chuck of a hammer drill ofclaim 1 wherein said tool element is a chisel.

3. The system for preventing rotation to a tool element in the chuck of a hammer drill ofclaim 1 wherein said shank of said tool element is positioned within said first opening of said body by Allen screws.

4. The system for preventing rotation to a tool element in the chuck of a hammer drill ofclaim 1 wherein said shank of said tool element is positioned within said first opening of said body by a quick-connection configuration.

5. The system for preventing rotation to a tool element in the chuck of a hammer drill ofclaim 1 wherein said shaft of said drill member is positioned within said chuck of said hammer drill by a quick-connection configuration.

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